Add twig/string-extra extension

extra/string-extra/tests/IntegrationTest.php

@@ -0,0 +1,30 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Twig\Extra\Markdown\Tests;
+
+use Twig\Extra\String\StringExtension;
+use Twig\Test\IntegrationTestCase;
+
+class IntegrationTest extends IntegrationTestCase
+{
+    public function getExtensions()
+    {
+        return [
+            new StringExtension(),
+        ];
+    }
+
+    public function getFixturesDir()
+    {
+        return __DIR__.'/Fixtures/';
+    }
+}